1. Field of the Invention
The invention concerns a method for calendering a paper or cardboard web.
2. Discussion of the Related Art
A method of this kind is known from European patent application No. 0 141 614 A2. A long calendering zone is formed between a smooth casing of a heated roller and a belt which partly wraps around the casing. An as yet uncalendered paper or cardboard web is more or less dried or wetted with respect to the web thickness and then the wetter side of the web is pressed against the casing of the heated roller by means of the belt. One surface of the web is thus calendered during the dwell time in the calendering zone. The desired calendering process thus takes place on only one side of the web. During the calendering process, the application of temperature and pressure in the calendering zone is complex and difficult to monitor.
An object of the invention is to provide a method for calendering a paper or cardboard web, in which a web which is still wet can be calendered as desired at any given time without first having to produce an asymmetrical moisture profile with respect to the web thickness in an elaborate way. At the same time the application of pressure and temperature during the calendering process should be easy to survey and regulate.